What’s So Great About Barges?

From the Triloboats.com FAQ:

What are the advantages of the Barge shape?

The prime advantage is a barge’s increased displacement. That means you can carry more stuff.

A barge is very nearly a rectangle, which displaces the maximum amount on a given beam, draft and length. Any shape which carves away from that volume with rocker, flare, rounded bilges or plan view curvature (e.g., curving in to a point or transom), will drop in displacement. To illustrate:

barge vs. sharpie

Barges carry all that extra displacement well outboard with firm bilges and flat runs amidships. This means they are initially stable and not prone to pitching, though their motion, if light, may be quick. They can carry, or stand up to more sail on given dimensions than other boats.

Contrary to what you may have heard, barges have more reserve stability, on a given dimensions, than any other hull form. When you hear otherwise, the comparison is “cooked” by adding flare to the bottom beam and claiming victory (sorry, sharpies and dories always tend narrower than a barge on the same length)—this increases overall beam, of course… if you let the barge catch up, it wins in both initial and reserve buoyancy. The curve of buoyancy is different, however, than in a flared hull. A barge’s reserve is small in proportion to its large initial stability, the reverse of the common case. This means that the transition between upright and stable and knock-down, while harder to bring about, isn’t going to linger as long in-between, a fact which should be kept in mind if you insist on sailing on your ear.

Here’re a few other barge advantages (I’ll include summaries of the above):

  • Generally, barges are relatively inexpensive to build. They maximize volume vs. surface area (e.g. material cost).
  • Maximum displacement on a given overall dimensions (length, beam, draft).
  • Adequate displacement on short length saves money in harbors and, in our area, taxes. Both charge by LOA.
  • Maximum form stability for the same givens (this, to me is a critical virtue). Bolger comments that the “box” chines act like a narrow catamaran, with displacement outboard for increased form stability. As a bonus, the very hard chines are roll-damping and track well.
  • Maximizes stowage: Unfortunately, the best area of any boat is along the mid-line, and that’s given over to empty space (gangway). Side and bottom curvature cut away from volume along the hull, which means cutting into stowage. Barges hold this to a minimum.
  • Right angle stowage along the chines (vs. roughly triangular spaces in the typical boat). This allows very cheap and easy storage solutions in comparison to most hull shapes (at least in smallish boats where one is always living near the hull. It almost eliminates the need for special solutions for straight gear against a curvy hull.
  • Barges have a dead flat run, which allows sitting upright on a beach, and a flat sole with constant headroom.
  • Barges maximize deck-space, enabling easy and cheap solutions for such things as boat covers, gear stowage, PV foot-print, dinghy stowage. There is more space for clear paths forward and lots of room to work anchor gear, both of which are important safety considerations.

Whew! Aren’t you glad you asked?

How do TriloBoats differ from barges in general?

TriloBoats maximize whole and half-sheet construction, and right angles:

  • Whole and half-sheet construction, joined in line or at right angles (only a few exceptions) holds layout, cutting, beveling, joining, truing, spiling and a multiplicity of parts to a bare minimum. These details add up to long projects. Eliminating them makes for radically shorter building times.
  • They are easy to design: graph paper works fine without the learning curve and time required to fair curves between views. You can build from notes without laboring over a “fair copy”.
  • They can be built with basic carpentry skills; kids can pitch in at high levels throughout the project.
  • Easy right angle joints (built up from factory milled faces) require less expensive glue (gapless joins) and eliminate weakness in situations where the glue is weaker in the gap (e.g., liquid polyurethane).
  • Allows building with sheet materials (ply, copper, foamboard, etc): sheets plank a boat very quickly and complement water-PROOF, monocoque construction. Barring a breach, your bilges should be reliably dry.
  • Right angle chines can be protected with common angle iron or bronze, which can also cover the joint between side and bottom copper plates. Great for settling down on not-quite-rock free beaches while swinging in wind or current.
  • TriloBoats are easy to move. They have great planes for jacking, and, with their long, flat run, rollers work well under the hull (continuous rocker tends to make uphills of every roller, concentrates load on one, and often bottoms out on the downside, stalling progress and endangering fingers and toes or worse). Their monocoque, girder construction makes them very robust (you can jack anywhere in the vicinity of an edge or bulkhead and no torquing worries). Traditional boats must be handled carefully, and often require moving cradles.

What’re the DISadvantages of the TriloBoat shape, and will they be able to sail?

I’m betting that they will be decent (not stellar) sailors.

The following are TriloBoat cons:

  • They have high windage, relative to their “grip” on the water.
  • Their upwardly curved, flat bottom at the bow won’t be cleaving a chop (interestingly, though, the super blunt bow of Dutch boats is often explained as providing extra buoyancy to lift them up and over the nasty chop of the North Sea—Andy has had his T32x12 in 5 ft chop on the edge of the Gulf of Alaska. He reports no undue pounding and good progress under light power (8hp outboard)).
  • Their heeled waterline is going to be one weird, fat banana (technical terms that bode not well).

HOWEVER:

  • A shoal hull, so long as you don’t plow water with a transom, doesn’t have far to shoulder water aside, allowing even a broad bow to ease through the water.
  • When heeled, their hard chine becomes a V, which slips along and tracks well.
  • Their high stability allows them to carry more sail.
  • Off the wind, they are a toboggan, or skimming dish, or belly-whopper (take your pick).

My conclusion (re enforced by our experience on LUNA, which is what you get when you cross a barge with a sharpie) is that they will make reliable sailors. By that I mean that they can work steadily to windward (albeit slowly) in heavy weather. Off the wind, they’ll fly.

Here’s a pic of the ALMA (taken by Charlie Bergstedt), close-hauled and sailing to windward in what looks to be about 15 knots of wind, and her lines, which are reasonably close to a wide TriloBoat’s:

Alma

ALMA’s not heeling discernibly, despite flying all her working sail (main tops’l not set). She’s dragging no large wake, and by her angle to waves and flags, appears to be 50° or less off the wind (not bad for a sailing palace!). All these point to decent sailing qualities.

TriloBoats have an easier entry than she does (ALMA is built “backward” relative to modern thinking—blunt in the bow, easier at the stern). She carries a “broad bone in her teeth” (the white splash across the bow). Any pitching tends to throw water forward, absorbing energy that would be better used for speed. This is endemic to boats whose bottoms curve up and out of the water (sharpies, barges, scows, garveys, skipjacks and dories… not all do, but it’s more rule than exception). Nevertheless, many of these are known as fast types.

Originally posted 2012-04-30 06:48:47.

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1 COMMENT

  1. This is a great article. I wish we could get Dave and/or Anke to guest author.

    I didn’t think you could argue that a barge makes a fast or efficient boat (clearly I’m not proven wrong), but I hope to appreciate its stability, capacity and space.

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